The main objectives of this research are to study neural mechanisms regulating ACTH and growth hormone (GH) secretion in the rat. Several projects will attempt to identify structures responsible for rhythmic and stress-induced ACTH secretion and for the feedback regulation of the pituitary-adrenal system. Other experiments will explore the control of growth and plasma GH levels; a major aim is to determine the neuroendocrine basis for augmented growth and plasma GH levels resulting from isolation of the medial basal hypothalamus. Related projects will study structures mediating stress-induced decreases in GH secretion. A final series of projects will focus on the neural basis for stress-induced alterations in prolactin and LH secretion. BIBLIOGRAPHIC REFERENCES: Rice, R.W., J. Kroning and V. Critchlow. Effect of stress on plasma corticosterone and growth hormone levels in rats with median eminence-pituitary islands. Neuroendocrinology 19:339-351, 1975. Rice, R.W., J. Kroning and V. Critchlow. Sex differences in the effects of surgical isolation of the medial basal hypothalamus on linear growth and plasma growth hormone levels in the rat. Endocrinology 98:982-990, 1976.